<template>
  <div>
    <h4 :style="{ marginBottom: '20px' }" v-if="title">{{ title }}</h4>
    <v-chart v-if="dataSource.length>3" key="2" :forceFit="true" :onClick="handleClick" :height="height" :data="data">
      <v-tooltip ref="tooltip" style="display:none;" />
      <v-axis/>
      <v-legend/>
      <v-stack-bar :position="position" :color="this.xField" />
    </v-chart>
    <v-chart v-else key="1" :forceFit="true" :onClick="handleClick" :height="height" :data="data">
      <v-tooltip ref="tooltip" style="display:none;" />
      <v-axis/>
      <v-legend/>
      <v-stack-bar :position="position" :color="this.xField" :size="40" />
    </v-chart>
  </div>
</template>

<script>
import { DataSet } from '@antv/data-set'
import { ChartEventMixins } from './mixins/ChartMixins'

export default {
  name: 'BarStack',
  mixins: [ChartEventMixins],
  props: {
    title: {
      type: String,
      default: ''
    },
    dataSource: {
      type: Array,
      default: () => [
        { type: 'Jeecg', 'Jan.': 18.9, 'Feb.': 28.8, 'Mar.': 39.3, 'Apr.': 81.4, 'May': 47, 'Jun.': 20.3, 'Jul.': 24, 'Aug.': 35.6 },
        { type: 'Jeebt', 'Jan.': 12.4, 'Feb.': 23.2, 'Mar.': 34.5, 'Apr.': 99.7, 'May': 52.6, 'Jun.': 35.5, 'Jul.': 37.4, 'Aug.': 42.4 }
      ]
    },
    fields: {
      type: Array,
      default: () => ['Jan.', 'Feb.', 'Mar.', 'Apr.', 'May', 'Jun.', 'Jul.', 'Aug.']
    },
    // 别名，需要的格式：[{field:'name',alias:'姓名'}, {field:'sex',alias:'性别'}]
    aliases: {
      type: Array,
      default: () => []
    },
    height: {
      type: Number,
      default: 254
    },
    xField: {
      type: String,
      default: 'type'
    },
    yField: {
      type: String,
      default: ''
    }
  },
  data() {
    return {
      position: 'x*' + (this.yField ? this.yField : 'y')
    }
  },
  computed: {
    data() {
      if (this.yField) {
        return this.dataSource
      }
      const dv = new DataSet.View().source(this.dataSource)
      dv.transform({
        type: 'fold',
        fields: this.fields,
        key: 'x',
        value: 'y'
      })
      // bar 使用不了 - 和 / 所以替换下
      const rows = dv.rows.map(row => {
        if (typeof row.x === 'string') {
          row.x = row.x.replace(/[-/]/g, '_')
        }
        return row
      })
      // 替换别名
      rows.forEach(row => {
        for (const item of this.aliases) {
          if (item.field === row.x) {
            row.x = item.alias
            break
          }
        }
      })
      return rows
    }
  }
}
</script>
